First things first then

Change this to allow any indexes to be used. Always do the convert on the scalar data if possible
CONVERT(char(10),formreceiveddate, 103) <> '01/01/1900'
to
formreceiveddate <> CONVERT(datetime,'01/01/1900',103)

Secondly, this will be much neater if you just dump out the data grouped by the sales rep and week and use Excel or ASP to diplay it the way you want. Hence the query will be

SELECT pmr.pmrname, (datepart(cor.formreceiveddate) - 1) / 7 + 1 as [week], count(p.patientid) as [Patients]
FROM
doctor d,
clinic c,
pmr pmr,
patient p,
course cor
WHERE
d.clinicid=c.clinicid
AND
c.pmrid=pmr.pmrid
AND
pmrname='Bruce Tham'
AND
d.doctorid=p.doctorid
AND
cor.patientid=p.patientid
AND
formreceiveddate <> CONVERT(datetime,'01/01/1900',103)
GROUP BY pmr.pmrname, (datepart(cor.formreceiveddate) - 1) / 7 + 1